X-ray irradiation apparatus

ABSTRACT

An X-ray beam emitter including a vacuum chamber having a target window. An electron generator is positioned within the vacuum chamber for generating electrons that are directed at the target window for forming X-rays. The X-rays pass through the target window in an X-ray beam.

RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/277,322 filed on Mar. 20, 2001. The entire teachingsof the above application are incorporated herein by reference.

BACKGROUND

[0002] Many medical instruments are reusable and require sterilizationbetween uses. Some of these instruments, for example, endoscopes andgastroscopes, are difficult to fully sterilize. Typically, suchinstruments are sterilized by hydrogen peroxide which is flushed throughthe interior as well as over the exterior of the instruments. This isnot only a time consuming process, taking about one hour, but often theinstruments have contaminated areas which the sterilizing process cannotsufficiently penetrate to fully sterilize such as biofilms of bacteria.In addition, the hydrogen peroxide is not able to kill all viruses.Another common sterilization agent is ethylene oxide which producessimilar results. Other methods of sterilization include irradiation withgamma radiation, but this method can take up to 24 hours with currentequipment.

SUMMARY

[0003] The present invention includes an apparatus that can be employedfor sterilizing articles such as medical instruments more quickly andthoroughly than current methods. The present invention includes an X-raybeam emitter having vacuum chamber with a target window. An electrongenerator is positioned within the vacuum chamber for generatingelectrons that are directed at the target window for forming X-rays. TheX-rays pass through the target window in an X-ray beam.

[0004] In particular embodiments, the target window has a thicknesswhich substantially prevents the passage of electrons therethrough. Theelectrons and X-ray beam travel in substantially the same direction. TheX-ray beam is directed into an irradiation region for irradiatingarticles positioned therein. In some embodiments, the emitter is asterilization device where articles irradiated by the X-ray beam aresterilized.

[0005] The X-ray beam emitter can be part of an X-ray beam system in anX-ray irradiation apparatus which includes at least one X-ray beamemitter for directing at least one X-ray beam into an irradiationregion. In particular embodiments, the X-ray beam system includes morethan one X-ray beam emitter for directing X-ray beams into theirradiation region from different directions. In one embodiment, atleast three X-ray beam emitters are positioned around the irradiationregion thereby forming a central irradiation chamber. In anotherembodiment, six X-ray beam emitters are positioned in a ring around theirradiation region and abut against each other. The X-ray beam systemmay include more than one ring of X-ray beam emitters which are joinedtogether. In some embodiments, the apparatus is a sterilizationapparatus where articles are positioned within the irradiation chamberfor sterilization.

[0006] The present invention also includes a method of forming X-rays.The method includes providing a vacuum chamber having a target window.An electron generator is positioned within the vacuum chamber forgenerating electrons. The electrons are directed at the target window toform X-rays which pass through the target window in an X-ray beam. Thetarget window has a thickness which substantially prevents the passageof electrons therethrough. The electrons and the X-ray beam travel insubstantially the same direction.

[0007] When employed for sterilization purposes, the X-ray beamsgenerated by embodiments of the present invention are able to deeplypenetrate into the articles being irradiated. Both surface and imbeddedcontaminants are able to be irradiated for relatively quick and thoroughsterilization in comparison to traditional methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

[0009]FIG. 1 is a simplified end view of an embodiment of the presentinvention X-ray beam irradiation apparatus.

[0010]FIG. 2 is a simplified perspective view of the X-ray beamirradiation apparatus of FIG. 1.

[0011]FIG. 3 is a side view of another embodiment of the presentinvention X-ray beam irradiation apparatus.

[0012]FIG. 4 is an end sectional view of an embodiment of an X-ray beamemitter in accordance with the present invention.

[0013]FIG. 5 is a side sectional view of the X-ray beam emitter of FIG.4.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to FIGS. 1 and 2, X-ray beam irradiation apparatus 10is suitable for sterilizing objects or articles, for example, medicalinstruments, tools or components. In the embodiment depicted in FIGS. 1and 2, X-ray beam irradiation apparatus 10 includes an x-ray beam systemhaving an X-ray irradiation unit 11 for irradiating articles 19. TheX-ray irradiation unit 11 of the embodiment depicted in FIGS. 1 and 2includes a series of X-ray beam emitters 12 each having a target window16 through which an X-ray beam 22 is generated. The X-ray beam emitters12 have angled side walls 14 which allow the X-ray beam emitters 12 tobe abutted against each other and joined together in a ring 10 asurrounding an irradiation region or chamber 20 so that the X-ray beamemitters 12 can direct the X-ray beams 22 radially inwardly intoirradiation chamber 20 from different directions. FIGS. 1 and 2 depictsix X-ray beam emitters 12 abutted against each other to form ahexagonal shaped irradiation chamber 20. The target windows 16 areclosely positioned to each other so that the X-ray beams 22 directedinto irradiation chamber 20 combine to provide substantially continuousradially inward X-ray beam coverage.

[0015] In use, articles 19 (FIG. 1) such as medical instrumentsrequiring sterilization are typically positioned within irradiationchamber 20. Doors, such as those shown in FIG. 3, designated byreference numeral 26, may be employed on opposite ends of irradiationchamber 20 to provide shielding of the X-rays. Alternatively, elongatedentrance and exit tunnels can be employed to provide shielding. Power tothe X-ray beam emitters 12 is then provided so that X-ray beams 22 aredirected inwardly into irradiation chamber 20. The X-ray beams 22 areable to disable, damage or kill bacteria, viruses, and organisms on thesurface of the article 19. In addition, the X-ray beams 22 can penetrateinto the article 19 to sterilize regions deep within the article 19 aswell as penetrate and sterilize thick layers or regions ofcontamination. Instruments such as an endoscope may require asterilization time of about a half hour at a low power of 5 kW peremitter 12 to achieve thorough sterilization. This is about half thetime in comparison to the one hour typically required when sterilizingwith hydrogen peroxide. Even over such an amount of time, instrumentssterilized by hydrogen peroxide are not as thoroughly sterilized as inthe present invention.

[0016] Although six X-ray beam emitters 12 are shown in FIGS. 1 and 2 toform X-ray irradiation unit 11, it is understood that any number ofX-ray beam emitters 12 can be employed. When three emitters 12 areemployed, irradiation chamber 20 can be triangular in shape, with fouremitters 12, square, and with five and above, polygonal. When multipleemitters 12 are employed, irradiation chamber 20 can also haveconfigurations that are wide and flat, or convoluted, depending upon thesituation. In some cases, X-ray irradiation unit 11 may only need one ortwo X-ray beam emitters 12. In such cases, reflectors for reflectingX-rays can be used in combination with the X-ray beam emitters 12.Additionally, although x-ray emitters 12 have been shown to be joinedtogether in a ring 10 a, alternatively, one or more X-ray emitters 12may be positioned for providing X-ray beams that are not in asubstantially continuous circle, for example, from one or twodirections. When two X-ray beam emitters 12 are employed, the emitters12 can be arranged in opposed fashion.

[0017] Referring to FIG. 3, X-ray beam irradiation apparatus 24 isemployed when sterilizing articles 19 that are too long to fit withinapparatus 10. X-ray beam irradiation apparatus 24 includes an X-ray beamsystem having more than one X-ray irradiation unit 11 joined together.In one embodiment, each X-ray irradiation unit 11 includes a ring 10 aof X-ray beam emitters 12 similar to that depicted in FIGS. 1 and 2. Therings 10 a are abutted against each other and joined together so thatthe irradiation chambers 20 of each ring 10 a join together collectivelyto form one long irradiation region or chamber 28. Three X-rayirradiation units 11 are shown abutted together, however, less thanthree or more than three units 11 can be joined together. Typically,X-ray beam irradiation apparatus 24 includes doors 26 to provideshielding of the X-rays. Although instruments are typically positionedin a stationary manner within irradiation chamber 28, alternatively, aconveyor system can be employed to slowly move articles 19 throughirradiation chamber 28. The conveyor system may include conveyor beltsand/or rollers. When a conveyor system is employed, entrance and exittunnels may be desirable to provide shielding.

[0018] It is understood that X-ray irradiation apparatus 24 can haveX-ray irradiation units 11 of configurations that are different thanring 10 a such as discussed above. In addition, some embodiments of theirradiation units 11 can include mechanisms for moving one or moreemitters 12 over or around an article 19 for providing X-ray irradiationwith a minimum number of emitters 12. In one embodiment, a ring 10 a istranslated longitudinally along article 19. In another embodiment, anemitter 12 is rotated around article 19 and can also be translatedlongitudinally over article 19. In configurations where an emitter 12 isrotated around article 19, employing more than one emitter 12 can reducethe amount of rotation required. For example, if two emitters 12 areemployed positioned in opposed fashion, the emitters 12 can be rotatedonly 180° around article 19.

[0019] In addition to sterilizing medical instruments, tools orcomponents, X-ray beam irradiation apparatuses 10 and 24 can be employedto sterilize implantable devices or components such as artificialjoints, pins, plates, pumps, pacemakers, etc. Furthermore, a widevariety of objects or articles 19 can be sterilized, including items foruse in a sterile room or environment. In some instances, it may bedesirable to sterilize substances such as powders, liquids or fooditems. Referring to FIG. 3, X-ray beam irradiation apparatus 24 can beemployed as a sterilizing entrance for articles 19 entering a sterileenvironment where one end of apparatus 24 is connected to the sterileenvironment, typically, extending through a wall thereof. One door 26allows articles 19 to be inserted into apparatus 24 from the exteriorfor sterilization. The other door 26 allows removal of the sterilizedarticle 19 from apparatus 24 into the sterile environment.

[0020] Referring to FIGS. 4 and 5, X-ray beam emitter 12 in oneembodiment includes a hermetically sealed vacuum chamber 30 having arectangular target window 16 positioned at one end thereof. An electrongenerator 32 is positioned within the interior 30 a of vacuum chamber 30for generating electrons e⁻ which are accelerated towards the targetwindow 16 for forming X-rays. The target window 16 typically consists ofa thin metallic foil that has a thickness sufficient to substantiallyprevent the passage of electrons e⁻ through while allowing passage ofX-rays. The target window 16 is supported by a support plate 38 having aseries of holes 38 a therethrough which allow the electrons e⁻ to reachtarget window 16. In some embodiments, outwardly angled holes 38 b maybe included at the far ends of support plate 38 (FIG. 5) to direct moreelectrons e⁻ to the ends of target window 16. The target window 16 issealed to support plate 38 by bonding under heat and pressure, butalternatively could be brazed or welded. In one embodiment, the targetwindow 16 can be 12 inches long so that irradiation chamber 20 is about12 inches long. When X-ray beam emitters 12 are to be abutted againsteach other in a ring such as ring 10 a (FIG. 1), the emitters 12 canhave angled sides 14 which extend towards and near the longer sides ofthe target window 16 (FIG. 4). Sides 14 are angled at about 60° when sixemitters 12 are abutted together, however, the angle of sides 14 candiffer depending upon the number of emitters 12 joined together. In someirradiation chamber 20 configurations, the angled sides 14 can beomitted, for example, in some rectangular configurations. A tube may beextended from vacuum chamber 30 and connected to a vacuum pump forevacuating vacuum chamber 30 which is then sealed off to hermeticallyseal vacuum chamber 30.

[0021] The electron generator 32 has a filament housing 34 which in oneembodiment is disc shaped and has a series of openings in the bottom 34a. Tungsten filaments 36 are positioned within housing 34 for generatingthe electrons e⁻. Filament housing 34 is electrically connected to ahigh voltage supply by tubular conductor 40 a and cable 18. Commonranges are 100-300 kV with 125 kV being typical. In some applications,voltages 100 kV and above 300 kV may be desirable. Target window 16 iselectrically grounded to impose a high voltage potential betweenfilament housing 34 and target window 16. Filaments 36 are providedpower by a filament power supply electrically connected to cable 18 andare electrically connected at one end to a conductor 42 extending withinthe interior of filament housing 34, and are electrically connected atthe other end to a conductor 40 b extending from cable 18. The upperportions of conductor 40 a is embedded within insulating materials 44.

[0022] In use, the filaments 36 are provided with power to heatfilaments 36 to about 3400° F. to 4200° F. which causes free electrons eto form on filaments 36. The high voltage potential imposed between thefilament housing 34 and target window 16 causes the free electrons e onfilaments 36 to accelerate from the filaments 36 in a beam throughopenings in the bottom 34 a of filament housing 34 to target window 16.The target window 16 is typically a thin foil of gold, titanium ortungsten about 3 microns thick which substantially blocks or preventsthe passage of electrons e⁻ therethrough, but, alternatively, may beformed of titanium with a layer of gold thereon, or be formed of goldwith copper or silver. Typically, metals with a high Z number and goodthermal conductivity are preferred, but it is understood that thematerial of target window 16 can vary depending upon the application athand. For example, materials and combinations other than those describedabove can be used. The electrons e⁻ striking the target window 16typically do not pass through but instead form X-rays which exit oremerge from the target window 16 in an X-ray beam 22 and continue totravel substantially in the same forward direction as the electrons ewere traveling. In other words, the beam of electrons e⁻ is transformedor changed by target window 16 into the X-ray beam 22 resulting in acontinuous two-part or stage beam where the first stage is formed by thebeam of electrons e⁻ and the second stage is formed by the X-ray beam22. The X-ray beam 22 exits target window 16 with substantially the sameoutline as target window 16. The production of X-rays in this mannerprovides a relatively efficient broad X-ray beam 22 because both theelectrons e⁻ and the X-ray beam 22 are traveling in the same forwarddirection. The beam of electrons e⁻ and the X-ray beam 22 are shown tobe perpendicular or substantially perpendicular to target window 16. Insome situations, electrons e might strike target window 16 at an angle.

[0023] In some embodiments, target window 16 may be configured to allowsome electrons e to pass through to provide a mix of electrons e⁻ andX-rays. In further embodiments, the target window 16 can be replaced byan electron beam exit window which allows the electrons e⁻ to exit theemitters 12 in an electron beam. In such a case, the electrons e⁻ strikethe surface of the article to be sterilized thereby sterilizing thesurface and, at the same time, creating X-rays which sterilize theinterior. Such an embodiment can be used to sterilize or decontaminateany type of suitable equipment. The target window 16 can be configuredto suit particular arrangements, and can be of shapes other thanrectangular.

[0024] While this invention has been particularly shown and describedwith references to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the scope of the inventionencompassed by the appended claims. For example, features of the variousembodiments discussed above may be combined with each other or omitted.It is understood that the configuration, shape, dimensions, size andpower of X-ray emitter 12 can be varied depending upon the applicationat hand as well as the shape of the target window 16. Multiple emitters12 may be positioned side by side for generating an X-ray beam 22 fromone direction, or positioned in opposing directions for generating X-raybeams 22 from two directions. In some configurations, the X-ray beams 22from emitters 12 are not joined in a continuous manner. In addition,X-ray emitters 12 and apparatuses 10 and 24 may be employed to sterilizeany desired article, or may be used for other typical purposes, such astaking an X-ray of a patient or curing coatings.

What is claimed is:
 1. An X-ray beam emitter comprising: a vacuumchamber having a target window; and an electron generator positionedwithin the vacuum chamber for generating electrons that are directed atthe target window for forming X-rays which pass through the targetwindow in an X-ray beam.
 2. The emitter of claim 1 in which the targetwindow has a thickness which substantially prevents the passage ofelectrons therethrough.
 3. The emitter of claim 2 in which the electronsand X-ray beam travel in substantially the same direction.
 4. Theemitter of claim 3 further comprising an irradiation region into whichthe X-ray beam is directed for irradiating articles.
 5. The emitter ofclaim 4 in which the emitter is a sterilization device where articlesirradiated by the X-ray beam are sterilized.
 6. An X-ray irradiationapparatus comprising: an X-ray beam system for directing at least oneX-ray beam into an irradiation region, the X-ray beam system comprisingat least one X-ray beam emitter, said X-ray beam emitter comprising: avacuum chamber having a target window; and an electron generatorpositioned within the vacuum chamber for generating electrons that aredirected at the target window for forming X-rays which pass through thetarget window as said X-ray beam.
 7. The apparatus of claim 6 in whichthe target window of the X-ray beam emitter has a thickness whichsubstantially prevents the passage of electrons therethrough.
 8. Theapparatus of claim 7 in which the electrons and X-ray beam travel insubstantially the same direction.
 9. The apparatus of claim 8 in whichthe X-ray beam system comprises more than one X-ray beam emitter fordirecting X-ray beams into the irradiation region from differentdirections.
 10. The apparatus of claim 8 in which the X-ray beam systemcomprises at least three X-ray beam emitters positioned in a ring aroundthe irradiation region, thereby forming a central irradiation chamber.11. The apparatus of claim 9 in which the X-ray beam system comprisessix X-ray beam emitters positioned in a ring around the irradiationregion and abutting each other.
 12. The apparatus of claim 10 in whichthe X-ray beam system comprises more than one ring of X-ray beamemitters joined together.
 13. The apparatus of claim 8 in which theapparatus is a sterilization apparatus where articles are positionedwithin the irradiation chamber for sterilization.
 14. The apparatus ofclaim 8 in which the X-ray beam system comprises at least oneirradiation unit having at least one X-ray beam emitter.
 15. Theapparatus of claim 14 in which the X-ray beam system comprises more thanone irradiation unit joined together.
 16. An X-ray sterilizationapparatus comprising: an X-ray beam system for directing at least oneX-ray beam into an irradiation region, the X-ray beam system comprisingat least one X-ray beam emitter, said X-ray beam emitter comprising: avacuum chamber having a target window; and an electron generatorpositioned within the vacuum chamber for generating electrons that aredirected at the target window for forming X-rays which pass through thetarget window as said X-ray beam, said X-ray beam for sterilizingarticles positioned within the irradiation zone.
 17. A method of formingan X-ray beam emitter comprising: providing a vacuum chamber having atarget window; and positioning an electron generator within the vacuumchamber for generating electrons that are directed at the target windowfor forming X-rays which pass through the target window in an X-raybeam.
 18. The method of claim 17 further comprising providing the targetwindow with a thickness which substantially prevents the passage ofelectrons therethrough.
 19. The method of claim 18 further comprisingconfiguring the X-ray beam emitter so that the electrons and X-ray beamtravel in substantially the same direction.
 20. The method of claim 19further comprising forming an irradiation region into which the X-raybeam is directed for irradiating articles.
 21. A method of forming anX-ray irradiation apparatus comprising: forming an X-ray beam system fordirecting at least one X-ray beam into an irradiation region, the X-raybeam system comprising at least one X-ray beam emitter; and providingthe X-ray beam emitter with a vacuum chamber having a target window, andan electron generator positioned within the vacuum chamber forgenerating electrons that are directed at the target window for formingX-rays which pass through the target window as said X-ray beam.
 22. Themethod of claim 21 further comprising providing the target window with athickness which substantially prevents the passage of electronstherethrough.
 23. The method of claim 22 further comprising configuringthe X-ray beam emitter so that the electrons and X-ray beam travel insubstantially the same direction.
 24. The method of claim 23 furthercomprising providing the X-ray beam system with more than one X-ray beamemitter for directing X-ray beams into the irradiation region fromdifferent directions.
 25. The method of claim 23 further comprisingproviding the X-ray beam system with at least three X-ray beam emitterspositioned in a ring around the irradiation region, thereby forming acentral irradiation chamber.
 26. The method of claim 25 furthercomprising positioning six X-ray beam emitters in a ring around theirradiation region and abutting each other.
 27. The method of claim 25further comprising forming the X-ray beam system from more than one ringof X-ray beam emitters joined together.
 28. The method of claim 23further comprising providing the X-ray beam system with at least oneirradiation unit having at least one X-ray beam emitter.
 29. The methodof claim 28 further comprising joining more than one irradiation unittogether to form the X-ray beam system.
 30. The method of claim 22further comprising forming the apparatus into a sterilization apparatusfor sterilizing articles positioned within the irradiation region.
 31. Amethod of forming an X-ray sterilization apparatus comprising: formingan X-ray beam system for directing at least one X-ray beam into anirradiation region, the X-ray beam system comprising at least one X-raybeam emitter; and providing the X-ray beam emitter with a vacuum chamberhaving a target window, and an electron generator positioned within thevacuum chamber for generating electrons that are directed at the targetwindow for forming X-rays which pass through the target window as saidX-ray beam, said X-ray beam for sterilizing articles positioned withinthe irradiation zone.
 32. A method of forming X-rays comprising:providing a vacuum chamber having a target window; positioning anelectron generator within the vacuum chamber for generating electrons;and directing the electrons at the target window to form X-rays whichpass through the target window in an X-ray beam.
 33. The method of claim32 further comprising providing the target window with a thickness whichsubstantially prevents the passage of electrons therethrough.
 34. Themethod of claim 33 further comprising configuring the X-ray beam emitterso that the electrons and X-ray beam travel in substantially the samedirection.